It was a mystery why people masturbate so often. The reason that it was a mystery was because it was not so common in the animal world. However, 2 evolutionary biologists, Robin Baker and Mark Bellis, solved this question by propounding an hypothesis claims that masturbating is beneficial for the human being.
Baker and Bellis has begun with their researches by examining the sex life of 30 heterosexual couple. For this, men were asked to masturbate before sex. The sperm examples during the orgasms were analysed. Then, the couples were asked to engage in a sexual intercourse and sperm examples were anaylzed that was discarded from woman body. After sexual intercourse, it was revealed that the sperm examples found in the men's body which was taken from the body of the woman was produced earlier than the other sperms!
Briefly stated, this thesis is based on a single biological fact: the sperm are getting old! Masturbation allows older sperm that have given up on their lives to be thrown out of the body and thus opens up young, live sperm in sexual relation. The younger the sperm in the male, the more likely it is to be accepted by the female reproductive system!
If we look at the evolutionary process: Men who masturbate in primitive times are more likely to be fathers, considering the possibility that the female mate with more than one men at a certain time. The situation changes a little bit, in women. The reason behind their masturbation is that they can generally grasp the orgasm more clearly, which in turn encourages women to have sex. It also focuses on the fact that the liquid removed from the body after masturbation can protect the vagina against bacteria.